1. Field of the Invention
The present invention relates to an inspection apparatus, an inspection method, an inspection system, and a storage medium and in particular to a processing technique for determining whether defective printing exists in a printed image.
2. Description of the Related Art
In recent years, a market called print on demand (hereinafter referred to as POD) has appeared. In the POD market, the use of a digital image forming apparatus (hereinafter referred to as an image forming apparatus) such as a digital copying machine and a digital multifunction peripheral, for example, realizes digital print using electronic data to enable print service to be performed.
In the digital print, an inspection apparatus is connected to the image forming apparatus to inspect whether a printing error, missing page or dirt in a print product delivered to a customer exists in-line. An in-line inspection processing allows the output processing of a print product to be changed depending on results of the inspection processing. For example, a print product, which is determined defective as a result of the inspection processing, can be output to a tray different from a tray for a non-defective article.
Laid-Open Japanese Patent Application No. 2000-123176 discusses a technique for inspecting a print product such that a reference image for inspecting the print product is compared with a scan image read by imaging the print product. The inspecting processing discussed in Laid-Open Japanese Patent Application No. 2000-123176 is one that a difference in tint between the scan image and the reference image is calculated to inspect the tint of the print product (hereinafter referred to as tint inspection).
Methods for specifying the color of the print product to be printed and output by the image forming apparatus include a method for specifying the color by a color mixture ratio among red (R), green (G), and blue (B), or among cyan (C), magenta (M), yellow (Y), and black (K), and a method for specifying the color by a color number or a color name given by of a color sample. The color sample is often simply called a color chart. In the latter method, a correspondence in values between the color number (or the color name) of the color sample and CMYK (or RGB) for representing colors indicated by the number (color name) is clearly defined by a print industry. In general, a user who wants to reproduce the color of the print product as faithfully as possible by the color of the color sample selects and specifies the color in the color sample.
The user who specifies color in an area by selecting the color in the color sample wants to reproduce the color of the color sample faithfully, so the user wants to sufficiently inspect the height of reproducibility of the color in the area. On the other hand, the area where the color in the color sample is not specified does not need to be higher in color reproducibility than the area where the color in the color sample is specified. For this reason, the tint inspection does not always need to be conducted using the same standard in the area where color is specified by the color mixture ratio and the area where color is specified by the color sample.
However, Laid-Open Japanese Patent Application No. 2000-123176 does not distinguish the area where color is specified by the color mixture ratio of RGB or CMYK and the area where color is specified by the color sample in the generated reference image, so that the processing contents of the tint inspection are not changed according to the area.